the new Qt based GUI should be just another alternative together with the GTK one. Also in the process more a clear core-GUI separation should be developed to enable other alternative GUIs (EFL,SDL/PyGame,Clutter/MX,etc.).

Most of the core GUI logic currently resides in the modRana "kernel" the modrana.py file. This logic needs to be transfered to a separate GUI module tat can be loaded by modRana at startup, either by providing a CLI parameter or automatically (once implemented).

There will be a platform independent API, implemented through and abstract parent class, that enables to interact with the current GUI module in platform independent way (toggle fullscreen, set window size, etc.).

This work will be partially based on Mieru, which already uses the concept of separate GUI modules & has advanced CLI argument support.

What needs to be done ?

add pluggable GUI module support DONE

move the current GTK logic to a GTK GUI module DONE

make sure the modularized GTK GUI works with all the changes DONE

add proper CLI argument handling DONE

-d, --device - set device module DONE

-u, --ui - set which GUI to use DONE

optional

--lat, --lon, --zoom, --layer - set a given map screen parameters at startup

--no_gps - don't start GPS on startup

--no_sound - disable sound on startup

--options_path - path to an alternate options.bin file (might be useful for debugging)

There are various methods for crossing the GML-native code(Python in this case) divide. Data access is available from bot sides - QML can access (specially crafted) Python properties and Python can fetch QML objects by name from the current QDeclarativeView.

Which way is better ? IMHO using Python properties and accessing them from QML code is cleaner and makes the QML/Python divide easily visible, PySide also makes it possible to implement callbacks and value change notifications - Python code can notify QML that value of a property changed so that QML code depending on its value can handle the change.

Directly calling QML objects from Python is on the other hand not visible from the QML code (unless manually documented). For isolated cases that (eq calling the shutdown method of the QML root object) it is IMO OK, overusage might cause the QML code to be too tightly connected with Python making it more suspect to breaking by changes in Python or QML.

ModRana consists from a number of more or less independent modules that communicate either by exchanging messages, directly calling methods of other modules or by proxy through the main modRana class. Each module has some task it is responsible for - mod_maptiles handles map tiles and mod_location handles location data.

There are basically two ways of providing the data from modules to the QML GUI - per module code exporting Python properties to the QML GUI or a central module (mod_QML_data) that grabs data from various modules and exports them through properties to QML.

For practical reasons, the second method seems to be the better one, at least at the moment:

as there would be just one QML GUI data handling module and other modules just providing GUI independent data, this aids GUI/backend separation

the data handling module can grab data from multiple modules and present them as a single property and even handle if a module is not loaded (might come handy once on demand module loading & unloading is implemented)

Another possibility for providing data to the QML gui is a simple interface, provided by the QML data module that accepts two arguments - module name and a key and returns a data value. The data module just passes the query to the given module and returns the result (it might also do some caching ?).

This might be implemented as an extension to the options api, something like:
options.mGet(location, sateliteCount, 0)
Would return the current satellite count or 0 if the location module did not return any data (it might not know the information or does not handle the sateliteCount key).

The options module just checks if a module with the given name exists, if it doesn't exist it returns the default value right away. If it exists it calls its getData method an provides the given key "sateliteCount" to the module. The module responds with a 2 item tupple. The first item represents if the module actually provides any data under this key - True=provides data, False=providing data for this key is not implemented. The second item is the result.

What needs to be done ?

create a new mod_QMLData module

provide the most important data & methods as Python properties to the QML code

location info (lat,lon,speed, direction, elevation, etc.)

layer ,zoomlevel

tile handling

POI handling

routing

text to speech

notifications

tracklogs

* implement the simple data API** add the mGet method to the options module and export it to modules** add the getData method to the base_module API

super-seeded by directly calling Python module methods

currently only for methods that don't take any arguments and return a single string, boolean, integer or float

Fortunately, the recent AGTL release for Harmattan has a nice QML map component that appears usable. In the future QGraphicsView based map widget is preferable, do to probable performance improvements and easier pseudo-3D handling.

Also a "navigation mode" with an opaque side/bottom bar might be needed while turn-by-turn navigation is in progress.

The current icon grid works quite nicely in both portrait and landscape and scales quite nicely to different (mobile) screen sizes. The big icons also help to easily navigate the icon grids. Generally all buttons should be fairly large so that it can be easily used while traveling/driving or in averse lighting conditions.

Tasks:

icon grid menu

should probably support kinetic scrolling with a small brightly colored "more" arrow near the border once there are more items displayed than visible

where to place the "escape" button ?

listable menu

a bar at bottom with the escape button and various context button/menu triggers

item count, search, delete, etc.

type-to-search on devices with keyboard

on devices without keyboard the user needs to first press to search icon to trigger the VKB

It might not be a bad idea to reimplement the Options menu structure using Qt Components. The main benefit would be in presenting more options at the screen and more usable components (switches, sliders, entry boxes, selection dialogs, etc.). On the other hand - how to handle this in QML-only environments ? This might not be an issue as Qt Components are now also available on Fremantle.

The POI view serves for display & management of the stored POI information. The view basically just needs to use the API of the current store_POI module.

POI currently have a name,description,latitude&longitude and a category. It might be sensible to add more items to the POI database (also Mappero appears to be defunct and there are no other users of the POI database format):

The search view provides search on online and offline resources. It might be good to provide a unified online & offline search interface that labels each result depending on source (online-nominatim, offline-POI database, offline OSM POI catalog, etc.). It should be also still possible to just search one online/offline category only.

Mostly the view just needs to use the already implemented module APIs. Some advanced features described in the previous paragraph might also need some backend work.

Also, routing might probably be rolled into search as it is just searching for a route from one place to another.

It might be a good idea to provide a way for modules to provided their own view in some standardized way. Eq. a new (possibly user provided/third party) module might just add its own view and register it in the main menu structure.

The most interesting at the moment is PyGame, which basically provides Python bindings for SDL. I don't have any personal experience with SDL so far but I'd guess it might be a little more lowlevel than GTK or Qt. On the plus side PyGamse is available for WebOS, being the only graphics toolkit with Python bindings on this platform so far. There is also a PyGame port for Android.

Having a proper package is very important on Harmattan due to Aegis restrictions. If an application needs to use location and other priviledged services, it needs to be properly packaged with an aegis manifest.

ModRana installs configuration files to ~/.modrana, so that they are writable & can be easily edited by the user (the configuration files are extensively commented for this reason). But when something changes in the default configuration file (say - a map layer URL) modRana needs to replace the installed configuration file and backup the existing one (so that any user-provided modifications are not lost).

Tasks:

only run upgrade check if modRana version changes DONE

add "revision" field to the configuration files DONE

stores current configuration file revision as an integer

the lowest valid value is 1

if an installed configuration file has a lower revision number than the default one, upgrade it DONE

MoDrana uses the idle loop to execute some workloads that are not time critical and uses timers to schedule actions that need to happen in the future. ModRana uses the cron module (it dosn't use the cron demon in any way) to provide an abstract API for this. The cron module currently uses GTK for the idle loop and timers.

While most parts of modRana are device independent and improvements translate to usage on most devices, modRana also needs to support hardware and features that are only available on a limited range of devices.